Sputtering under acceleration with engine light?

Hi,

The idea that the check engine light flashed indicates it was misfiring at that point. That can be caused by several things, but since the check engine light remained on, there will be diagnostic trouble codes stored.

What we need to do first is check what codes are stored. You need a scan tool to do this.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

If you don't have access to a scan tool, most parts stores will do it free of charge for you. Have that done, record the codes stored, and let me know what they are.

Take care,

Joe

Okay, I will do that today and let you know. Thanks

Okay, just one code and it's p0301 which he said was cylinder 1 misfire. It did run fine going there and back which is about 25 miles round trip.

Hi,

That is correct, a cylinder 1 misfire. It is hard to believe that it needs spark plugs already, but anything is possible.

In this case, I personally would remove the number 1 spark plug to check its condition. However, I suspect we may have a coil pack beginning to fail or the valve cover may have a leak and getting the coil wet. I say that because a spark plug is usually either good or not.

If you are comfortable doing it, here is what we need to try. We need to switch the coil packs between cylinders 1 and 2. The purpose is to determine if the coil pack is the issue. If the coil is failing, the misfire (P0301) will move to cylinder 2 (P0302). If you still have a misfire at cylinder1, then we need to check the spark plug.

I attached 3 pics below. The first two are the directions for removing the coils. They forgot to mention you need to remove a bolt. LOL In pic 3, I highlighted the bolts.

You only need to worry about cylinders 1 and 2. Cylinder 1 will be the one closest to the serpentine belt (front of the engine). Simply, remove the plastic cover from the top of the engine. Gently pull upward on it. I don't believe there are any bolts or screws holding it. It should snap into place.

Once that is removed, you will see the coil packs. Switch them and let me know what happens. Also, pay close attention to the rubber part of the coil that attaches to the spark plug. If it is wet with oil, that could also be the cause of the misfire.

Let me know if this helps, if you have other questions, or if I can help in any way.

Take care,

Joe

Got it, I can do that. Already checked #1 spark plug and looks normal wear to me. Will switch coil packs and have it checked again.

So got the same code after switching coil packs. I went to AutoZone this time. I was told they give a more detailed report. It said most likely solution was to reprogram the Power train Control Module. Are you buying that? Would it still be a good idea to put in new plugs anyway or is that not necessary?

I forgot to mention this model Forte 5 is the sport model with a turbo. If that has any bearing on the problem.

Hi,

Replace the PCM? LOL Heavens no!!! As far as the info I sent, it is relevant to this vehicle as well.

Okay, since the misfire didn't change cylinders, then we know the coil is good. So, now we need to make sure the spark plug is good and that it has spark. I need you to check that for me.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

Let me know what you find. Also, please don't replace the PCM or reprogram it. I can't see how that could be the cause.

Let me know.

Joe

Okay, done, and there is spark and I did do it on the #1 coil if that helps. And not to worry. I'm not going on any wild goose chases here, lol.

Hi,

If you have spark, that is good news. At this point, you need to have a live data scan tool connected to the OBD connector so you can see what is happening when this occurs. Since it is intermittent, that is what needs to be done to identify the issue.

Let me know if that is something you can do.

Take care,

Joe

If I could get my hands on one I probably could. Trouble is I don't see where I can rent one around here. Does it have to be a specific one for my car model? Any suggestions?

So, I have a question. I have a bad battery that needs replacing. Could that possibly have something to do with my problem? I get different answers online.

Hi,

Absolutely, it can affect drivability. Today's vehicles are very sensitive to voltage issues. As a result, sensors, or other components may not function properly.

I can't guarantee the battery is the cause, but it certainly can be a distributing factor.

Let me know what I can do to help.

Joe

Okay, will see about replacing that today.

Well new battery no change. At first it started sputtering earlier at about 2500-3000 revs then as I drove it for a bit it changed back to what it was doing before, sputtering at about 4k revs.

Hi,

That isn't good news. If we have spark and know the coil is good, we either have a sensor issue or an injector issue. At least that is my theory at this point.

Do you have a live data scan tool? I ask because we need to connect one and drive the vehicle while it is connected. Once it starts the issue, we need to check a few things. For example, what are the fuel trims when that happens, is the coolant temperature sensor providing accurate information, and so on?

Because this is intermittent, it is much more difficult to diagnose unless we can check things while they are happening or if we can retrieve freeze frame information via a scan tool providing that information.

Is that something you can get your hands on?

Let me know.

Joe

Well, if I need a high-end one to get the info you need, I don't see anything local I can rent or use. Is there something more economical I could get off Amazon that would do the job like the Bluedriver Bluetooth pro? I live in Sussex county DE so if you could take a quick look to see any options.
Also, when I changed the battery the check engine light didn't reset. Do I need to reset it and then drive it a certain distance to see if it works. Just wondering.

Hi,

You could drive it to see what happens. It certainly wouldn't let us know.

As far as a scan tool, you can get one with live data for under $40.00. I attached a pic below from Amazon showing one.

Let me know.

Joe

See pic below.

Wow cool. I had no idea those cheaper ones would be sophisticated enough. That's good news.

Opted for this one:

https://www.amazon.com/gp/product/B00UJV3E12/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

A little bit more but has a little better reviews and more of a track record and will be here tomorrow!

Hi,

Prices have come down a lot over the years. The newest thing is reading the can-bus. CAN stand for controller area network. Basically, the different modules in vehicles today are tied together via a few wires and communicate with each other. This type of scanner can identify codes regardless of the module storing them.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know how things turn out for you.

Take care,

Joe

So, I got my live scan tool today. It came later in the day, so I didn't have much time to mess with it. I did get a confirmation of the cylinder one misfire and went into the live data a bit. Now you're talking about the freeze frame. Does that happen when you have it in live scan mode, and does it just freeze frame all the info when the fault happens?

Hi,

It will automatically save the freeze frame data when the issue occurs. The scan tool doesn't even need to be connected. If the scan tool you have does retrieve freeze frame info, you should be able to check it now.

Let me know.

joe

So, this is actually the second freeze frame because I erased the codes and had to go and get the engine light to come on again. Sorry for doing it this way for some reason I can't print the freeze frame data from the PC.
They are in no particular order.

2

3

4

5

Hi,

I need to know something. Two things stick out to me, the IAT and STFT. (Intake air temperature and short-term fuel trim).

The STFT is high. In a perfect world, it would stay at 0%, but yours is at 23.4% which indicates the computer is trying to add fuel. Under normal conditions, the trims should stay between -10% and +10%. This can be the result of a weak fuel pump or an engine vacuum leak. However, the IAT makes me question it. The IAT temperature indicates 69F. I'm not sure where you are located, but that should be approximate under-hood temperatures. If you are in a very cold climate, I guess it could be okay.

I need you to check one more thing. See what the engine coolant temperature sensor indicates. It should be around 5 degrees difference. If it isn't, I suspect the IAT is failing.

Let me know.

joe

I believe what you're looking for is the ECT, same thing right? It shows 174 on the freeze frame data. And if it matters, I took it for a ride and watched the STFT and it varied about 7 points max either side of 0, and mostly around 2 points. It also showed similar IAT temperature.

Oh, and I live in Delaware which is a pretty moderate climate.

Hi,

The fuel trims sound good then. When you say the IAC showed similar readings, are you referring to what I read on the pic or did you get a reading similar to the ECT? And yes, the ECT is the engine coolant temperature sensor.

If the IAT was similar to the ECT, I wonder why it was off on the scan tool originally. The engine was at operating temperature when checked, correct?

Let me know.

Joe

No sorry, meant to say it was similar to the pic, in the 70s. And yes, it was at operating temperature.

The IAT is likely faulty. It should be showing a similar temperature as the ECT or under-hood temperature.

The IAT is integral to the manifold absolute pressure sensor (MAP). I attached a pic below showing its location.

Check the wiring to it, make sure the connector is in good condition, and I would recommend removing it for inspection. There shouldn't be that big of variance in the signals. Five- or ten-degrees difference I could suspect. This is way beyond that point.

Let me know what you find.

Joe

So found it think. This appears to be part of the MAP sensor or boost pressure sensor on turbo engines, right? That is what I'm seeing online anyway. I disconnected the harness and looked in perfect condition.

https://shop.advanceautoparts.com/p/fae-boost-pressure-senso-b4080454206fae/11894186-p?c3ch=PLA&c3nid=11894186-P&adtype=pla&product_channel=online&store_code=&gclid=Cj0KCQjw2cWgBhDYARIsALggUhoIpPiTCLZITXB8RBbMkhesIEkxKB0JgBbneQb2eJlUlz-IsB5opcEaAu_XEALw_wcB&gclsrc=aw.ds

Hi,

Yes, that appears to be correct. The IAT is integral to the MAP. Also, it can be referred to as a boost pressure sensor on a turbocharged engine.

Let me know what I can do to help.

Joe

So, I ordered a new sensor. Should be here Monday. I took the suspect sensor out to look at and noticed a film of oil on it. I couldn't see anything inside and stuck a long road inside and nothing also. I cleaned it up and took a ride and checked it again and nothing. Is this something to be concerned about? I really haven't driven it much since I've been retired. Mostly just local.

Hi,

When you disconnect the sensor, the computer sees it as an open circuit. To allow the engine to continue running, the computer substitutes another "fixed value" which is halfway between a rich and lean fuel mixture. As a result, the engine can run properly.

You should be fine until the new part arrives. If you told me you had to take a 1000-mile trip, I would be concerned. LOL

Let me know what you find or if you have questions.

take care,

Joe

So got my part today, earlier than expected. That's the good news. The bad news is it's reading basically the same. Does this thing need to be calibrated or something? I see mixed answers online. I disconnected the negative battery terminal. Is there something else going on causing this maybe?

Hi,

No, there isn't a relearn for this sensor. Do me a favor. Clear any codes and drive it to see if the same codes return.

Let me know.

Joe

So, I did that, and I also switched 1 and 2 coils again for the hell of it. Because I didn't clear the code the first, I did that. I did get the engine light to come. It flashed a couple times. So, no code generated, but there was a pending code and guess what? It was a cylinder 2 misfire. I'm guessing a pending code is one about to happen or something like that.
So, if I need a new coil should I replace all 4 and if so, the plugs as well? Or can I get away with just one for now to see if it fixes it?